Hey folks, I'm Andy, co-founder of BEEST, and my family makes spray foam for people who fix their own houses.

If your house sits on a crawl space, you know the morning walk to the kitchen.

Socks on. Slippers on. Floor still cold.

Rugs everywhere. Nobody sits on the floor. The dog sleeps on the couch.

Your floors aren't cold because of the flooring. They're cold because of what's under them.

Give me five minutes. I'll show you what's down there, why nobody fixed it, and how to seal it from your belly in a weekend.

Why Everything You've Tried Hasn't Worked

If your floors are cold, I'd bet you've tried most of this:

• Put down thicker rugs. Warmer feet. Same cold floor.
• Turned the heat up. The bill went up. The floor didn't change.
• Pushed batts up between the floor joists. Half of them are on the ground by now.
• Taped plastic over the cracks you could reach. It peeled off by February.
• Priced a crew. They wanted a minimum for a job under the house, if they called back at all.

None of it worked. And here's the part nobody told you: none of it touches the root cause.

The Hidden Root Cause: There's Winter Under Your Floor

A crawl space is a box of outside air under your house.

The walls of that box are bare block or concrete. The rim joist on top of them is bare wood, full of gaps.

Cold air comes in through those gaps and sits right under your floor all winter.

Somebody probably stapled fiberglass between the floor joists years ago. Go look. Half of it is hanging. Some of it is on the ground.

And even the batts still up there don't stop moving air.

So the floor you walk on is the only thing between you and winter.

That's the root cause. Not the flooring. Cold air pouring in at the crawl walls and the rim.

Why Nobody Told You This

Nobody wants to go down there. Including crews.

A crawl is tight, dirty, belly-down work. Most crews price it that way, if they'll do it at all.

The hardware store cans? Made for a door frame. Your crawl walls are about 480 square feet.

And everybody tells you to stuff more batts up into the floor. That's the hardest way to do it, and they fall down again.

The Fix: Seal the Crawl, Not the Whole Floor

Here's what most people get wrong. You don't foam the whole underside of the floor. That's about 1,500 square feet over your head, lying on your back. A poor fit for any kit.

You seal the crawl walls and the rim joist instead. That's about a third of the area.

Vapor retarder on the ground first. Then foam on the walls and the rim, so the cold air stops pouring in under your floor.

That's what FullStop is for. A 12-can kit with a real metal gun, not a single can.

• 12 cans and a metal gun. Typical crawl walls are about 3 kits at 1 inch. Add 1 kit for the rim joist.
• R-4.12 per inch. Two 1-inch passes get you R-8.24 at 2 inches.
• DualCore foam. A closed-cell outer skin with a flexible center. People ask us open or closed cell. It's a blend of both.
• Class A fire-rated. Cured FullStop tested ASTM E84 with a Flame Spread Index of 0.* Your local code still decides whether it needs an ignition or thermal barrier, so check with your inspector.
• Gloves, goggles and a coverall in the box. Plus a metal gun and cleaner. Bring your own respirator.
• Not for wet crawls. Standing water or a wet wall? Fix that first. Foam goes on dry surfaces only.

How the Weekend Goes

Here's the job, start to finish.

1. Warm the cans to 68F. The crawl needs 41F or warmer, surface and air. Fall is best. A mild winter day works.
2. Lay the vapor retarder. Cover the ground first. Check that the walls are dry.
3. Suit up. Respirator, gloves, goggles, coverall. Kneepads and a headlamp help.
4. Practice on cardboard. Five minutes with the gun and you've got it.
5. Spray the rim first, then the walls. 1-inch pass. Use the extension tube in the tight spots. Let it set. Second pass for 2 inches.
6. Air it out. Keep the crawl ventilated and stay out of it for 24 to 72 hours.

Keep flames, sparks and pilot lights away while you spray and until the vapors clear. Follow the instructions in the box.

How Many Kits Does a Crawl Space Take?

This is the first question everyone asks. Here's the honest math.

One kit is 12 cans, rated 240 sq ft at 1 inch on paper. Real use runs about 70% of that. That's our estimate, not a lab test.

Measure the crawl wall height and the distance around the house. Multiply. A typical crawl is about 480 sq ft of wall.

Real use, rounded up. Overhead work uses more.

Round up, never down. One buyer put it best: “Covers less than you think it will, plan ahead.”

Bigger footprint? Use the calculator.

Use the calculator →

What Happened in Other People's Crawl Spaces

“Used in crawlspace area. Extremely easy to use even when cramped on your belly.”

“I used this to fill in the sill plate voids in the basement between the floor joists and the outside wall.”

“Surprised how easy this was. I had never used spray foam before this but it really was pretty simple after about 5 minutes.”

“Was nice to be able to speak with someone.”

FullStop customer reviews, Judge.me. Verbatim.

We asked our customers what changed after the job:

Customer-reported, individual experiences vary. Not a promise of savings from BEEST.

The Questions I Get Before People Buy

Does it work in a crawl space?

Yes for crawl space walls and the rim joist, with a vapor retarder on the ground first. Not for wet crawls. The extension tube helps in tight spots.

Is the gun too long for my crawl?

One buyer told us: “It's a good product but under house in close crawl space the unit is to long to spray bottom side of floor”. He's right about the floor. That's why we say do the walls and the rim, not the underside. Use the extension tube in tight spots.

Should I close my crawl vents?

That's a bigger decision about your whole crawl space. Check your local code and call us before you change the vents.

Is it flammable?

While you spray and before it cures, yes. Keep flames, sparks and pilot lights away until the vapors clear. Cured FullStop is Class A fire-rated (ASTM E84), Flame Spread Index 0.* Your local code decides whether it needs an ignition or thermal barrier.

I've never sprayed foam. Can I do this?

Plenty of our buyers had never touched foam before. Practice on cardboard, spray thin passes, let each one set, and you'll be fine.

Isn't it cheaper somewhere else?

The kit comes with a metal gun, cleaner, gloves, goggles, a coverall and video help. And a person who picks up the phone when you have a question halfway through the job.

Is this a real company?

We're BEEST, a family-owned company. Call us before you order and a real person answers: 1 (800) 540-4671.

Here's What I'd Do This Weekend

Grab a flashlight tonight. Open the crawl hatch and look at the walls and the rim.

Then pick a mild weekend. FullStop needs 41F or warmer, surface and air, so the sooner the better.